This invention pertains to a printer pen that can be recharged after the ink supply is depleted.
Certain ink-jet type printers, including those sold under the designation "DeskJet" by Hewlett-Packard Company of Palo Alto, Calif., use replaceable pens that carry an ink supply. A print head is attached to the pen body. The print head is operable for ejecting minute ink drops through orifices in the print head in a controlled manner while the pen is scanned across paper, thereby to produce the desired images or text.
The supply or reservoir portion of the pen contains reticulated polyurethane foam for storing the ink. The capillarity of the foam provides the necessary back pressure at the print head of the pen to prevent ink from leaking from the pen when the print head is not operated.
In the past, empty pens have not been refilled, even though such pens were otherwise fully functional. Instead, empty pens were disposed of and replaced with new, filled pens. Adding more ink to the foam material is difficult for a user who lacks the appropriate tools such as, for example, needles for injecting the ink under pressure into the foam. If a pen is to be refilled, it is important that a refill process take place relatively quickly so that the print head orifices do not become blocked with dried ink as a result of a lengthy refilling process.